Disclosed in patent application Ser. No. 14/087,552 is a powered version of a novel independent suspension system. The novel suspension system is a type of double A-arm suspension system derived from Ford's twin I-beam front suspension system, this novel suspension system being covered in patent application Ser. No. 14/059,062. While the powered version introduces a unique means of transmitting power from a powertrain to the wheels, the suspension system lacks a means of controlling the directional orientation of the knuckles, the knuckles being rotatably attached to the wheels.
Given that many types of production-based vehicles are routinely used in industries that involve off-road driving, e.g., construction, farming and ranching, mining, forestry, gas and oil exploration, where many obstacles—e.g., boulders, fallen trees, ravines, cliffs—exceed the limits of suspension travel, then automobile manufacturers and numerous other industries would greatly benefit from a powered version of this novel long travel suspension system that possessed the ability to control the directional orientation of both the steering and non-steering knuckles, particularly for a four wheel drive (4WD) vehicle.
Controlling the directional orientation of the knuckles in a production-based vehicle equipped with front and rear independent suspension systems typically involves tie rods: in the case of the steerable (usually front) knuckles, the tie rods operate with other parts of a steering system; whereas in the case of the non-steerable (usually rear) knuckles, the tie rods operate with one of their ends being attached to a rigid body such as the frame, cross-member, or bracket assembly. Also, most 4WD vehicles equipped with a double A-arm front suspension system employ a steering system that utilizes a tie rod to transmit steering input from the frame to the steering knuckle. Bump steer is minimized by aligning the ends of the tie rods with the ends of the A-arms. The same technique holds for a double A-arm rear suspension system. Functionally, the ends of the tie rods comply with the same coincidence principle as do the ends of the axle shafts. So long as the ends of the tie rods are coincident with the ends of the A-arms throughout suspension travel, then the tie rods will move in concert with the A-arms and the steerable (front) knuckles can be turned with minimal bump steer while the non-steerable (rear) knuckles can be locked into a straight-ahead direction with minimal change in toe throughout suspension travel.
Off-road vehicles equipped with Ford's twin I-beam front suspension system employ a type of swingset steering system. Typical swingset steering systems include a steering box, swingset lever arms, draglinks, and tie rods, the number of each component used depending on the application. As a type of idler arm, the swingset lever arm hangs vertically downward such that the top end is pivotally attached to the frame or cross-member while the bottom end can swing laterally parallel to a line passing through the front wheels, the top end being attached to the frame or cross-member in the same position as is the frame end of one of the I-beams. The steering box is attached to the driver frame side in the same position as the frame end of say the second I-beam. In applications involving one swingset lever arm, the swingset lever arm is attached to the passenger frame side in the same position as is the frame end of say the one I-beam. The steering box transmits steering input to the swingset lever arm via a draglink and to the passenger knuckle via the second tie rod while the swingset lever arm transmits steering input to the driver knuckle via the one tie rod. In applications involving two swingset lever arms, one and the second swingset lever arms are located at the driver and passenger sides of the vehicle in the same positions as are the frame ends of one and the second I-beams, respectively. The steering box transmits steering input to one swingset lever arm via one draglink. The one swingset lever arm transmits steering input to the second swingset lever arm via a second draglink and to the passenger knuckle via the one tie rod while the second swingset lever arm transmits steering input to the driver knuckle via the second tie rod.
In principle a type of swingset steering system is suitable for the present invention so long as it's compatible with the suspension system covered in patent application Ser. No. 14/059,062. In particular, a swingset lever arm linkage arrangement operating in conjunction with a front tie rod arrangement that is coincident with the front upper and lower leading links can transmit steering input from a steering box to the steering knuckles with minimal bumpsteer throughout suspension travel. Meanwhile, a rear tie rod arrangement that is coincident with the rear upper and lower leading links can lock the non-steering knuckles into a straight-ahead orientation with minimal change in toe throughout suspension travel. Thusly, the present invention offers a steering system design based on a swingset lever arm linkage arrangement that cooperates with tie rods as a means of contrail the direction orientation of both the steering and non-steering knuckles in the powered version of the novel independent suspension system disclosed in patent application Ser. No. 14/087,552.